Knowledge management system for computer-aided design modeling

ABSTRACT

A knowledge management system captures, stores, manages, and applies rules for modeling geometric objects and related non-geometric attributes. The knowledge management system controls a computer-aided design system for modeling a geometric structure. The knowledge management system includes a knowledge management application in communication with the computer-aided design system through an application program interface. The knowledge management system also includes a central database managed by a knowledge storage application for maintaining rules and other related information. The knowledge management system also includes a knowledge acquisition application for generating rule programs for storage in the central database. The rules can relate to geometric and non-geometric attributes of the model.

FIELD OF THE INVENTION

The present invention relates generally to computer-aided design, and,more particularly, to a knowledge management system for computer-aideddesign modeling.

BACKGROUND OF THE INVENTION

Computer-aided design (CAD) systems can be used to produce andmanipulate geometric models. CAD systems often include verysophisticated algorithms for producing complex geometric models,manipulating those models, and analyzing the components of those models.For example, a CAD system may be used to model a complex structurehaving a curved surface, view the structure at various angles, andcalculate the surface area of the curved surface and the volume of thestructure as a whole. It might be useful to know the surface area of thecurved surface, for example, to determine how much paint would be neededto cover the surface. It might be useful to know the volume of thestructure, for example, to determine how much material would be neededto produce the structure.

While CAD systems can be very powerful modeling tools, they aregenerally limited to geometric modeling. Thus, CAD systems generallyrequire the user to apply product design rules and practices necessaryto produce the model. For example, if the user is required by anemployer to use certain practices (such as, for example, always using acertain size bolt to connect two components), then the user must applythose practices to the model. The user is typically also required tomake successive changes to a model when changing a component of themodel. For example, each time the user changes an attribute of acomponent (such as, for example, the outside diameter of a component),the user may have to change attributes of one or more other componentsthat connect or otherwise interact with that component, and the effectsof these changes may cascade through many components of the model. Theuser is typically also required to handle non-geometric attributes ofthe model (such as, for example, component pricing and manufacturingprocesses). As a result of these limitations, CAD systems can bedifficult to use, particularly for casual CAD users (such as engineers,architects, or managerial staff) who may not be proficient with the CADsystem but often need to make modifications to drawings or models on anas-needed basis.

Knowledge-based engineering (KBE) attempts to combine some level ofknowledge management with design automation. Knowledge managementtypically includes such things as best practices, lessons learned (e.g.,from earlier models), common practices (e.g., industry standards,company policies), product design rules, and quality metrics. Knowledgemanagement might be applied to design automation, for example, to reducethe number of parts a company needs to order (e.g., by reusing partsfrom one model in another model), reduce design time, reduce productcost, and produce higher quality and reliability. KBE functionality istypically implemented within a CAD system or as an add-on to a CADsystem (e.g., as a plug-in) so as to provide the CAD system withadditional knowledge management capabilities.

CAD systems are often used in conjunction with computer-aidedengineering (CAE) analysis tools for performing advanced model analysis.CAD systems are also often used in conjunction with product documentmanagement (PDM) tools for generating and maintaining productdocumentation. These CAE and PDM tools can be implemented as stand-aloneapplications or as add-ons to a CAD system. The KBE functionality mayinteract with the CAE and PDM tools to gather or provide information.

SUMMARY OF THE INVENTION

In various embodiments of the present invention, a knowledge managementsystem captures, stores, manages, and applies rules for modelinggeometric objects and related non-geometric attributes. The knowledgemanagement system controls a computer-aided design system for modeling ageometric structure, typically through an application program interfaceof the computer-aided design system. The knowledge management systemtypically includes a knowledge management application in communicationwith the computer-aided design system through an application programinterface. The knowledge management system typically also includes acentral database managed by a knowledge storage application formaintaining rules and other related information. The knowledgemanagement system typically also includes a knowledge acquisitionapplication for generating rule programs for storage in the centraldatabase.

Rule programs are generated by the knowledge management system based oninformation that can be provided by a user, imported from thecomputer-aided design system, or extracted from a product documentmanagement application. The rules can relate to both geometric andnon-geometric attributes of the model. Non-geometric attributes can bedependent on geometric attributes. Geometric structures can be modeledbased on rules relating to non-geometric attributes.

In certain embodiments of the present invention there is provided acomputer-aided modeling system includes a knowledge management systemfor managing a set of modeling rules and a computer-aided design systemcontrolled by the knowledge management system. The knowledge managementsystem generates instructions for modeling a geometric structure basedon the set of modeling rules and communicates the instructions to thecomputer-aided design system for generating a model of the geometricstructure.

The knowledge management system can include a knowledge managementapplication in communication with the computer-aided design systemthrough an application program interface of the computer-aided designsystem. The knowledge management system can also include a knowledgestorage application in communication with the knowledge managementapplication for storing the set of rules in a central database andcommunicating the set of rules to the knowledge management application.The knowledge management system can also include a knowledge acquisitionapplication in communication with the knowledge storage application forgenerating the set of rules and communication the set of rules to theknowledge storage application for storage in the central database. Theknowledge management system can produce a graphical display on agraphical user interface, including a first portion includinginformation from the knowledge management system and a second portionincluding information from the computer-aided design system (such as adisplay window including a graphical representation of the geometricstructure, with or without controls for manipulating the graphicalrepresentation).

In other embodiments of the present invention there is provided a methodfor computer-aided design modeling involves generating instructions formodeling a geometric structure based on a set of modeling rules andcommunicating the instructions to a computer-aided design system forgenerating a model of the geometric structure. In certain embodiments ofthe present invention, the set of rules are obtained from a centraldatabase over a communication network. The computer-aided design systemtypically includes an application program interface, and theinstructions are typically communicated to the computer-aided designsystem through the application program interface.

The method can also involve producing a graphical display on a graphicaluser interface, including a first portion including information relatingto the set of modeling rules and a second portion including informationfrom the computer-aided design system. This may involve directing awindow display generated by the computer-aided design system to bedisplayed on the graphical user interface. The display window caninclude a graphical representation of the geometric structure, and mayalso include controls for manipulating the graphical representation ofthe geometric structure.

In other embodiments of the present invention there is providedapparatus for computer-aided design modeling, the apparatus includes adesign modeler for generating instructions for modeling a geometricstructure based on a set of modeling rules and an interface from thedesign modeler to a computer-aided design system for communicating theinstructions to the computer-aided design system for generating a modelof the geometric structure. The apparatus typically also includes aninterface from the design modeler to a central database over acommunication network for obtaining the set of modeling rules from thecentral database. The computer-aided design system typically includes anapplication program interface, and the interface from the design modelerto a computer-aided design system typically complies with theapplication program interface.

In certain embodiments of the present invention, the apparatus includesa graphical user interface. The design modeler can produce a graphicaldisplay on the graphical user interface, including a first portionincluding information from the design modeler and a second portionincluding information from the computer-aided design system. This mayinvolve the design modeler directing a window display generated by thecomputer-aided design system to be displayed on the graphical userinterface. The display window can include a graphical representation ofthe geometric structure, and may also include controls for manipulatingthe graphical representation of the geometric structure.

In still other embodiments of the present invention there is provided acomputer program for computer-aided design modeling can be embodied in acomputer readable medium. The computer program includes means forgenerating instructions for modeling a geometric structure based on aset of modeling rules and means for communicating the instructions to acomputer-aided design system for generating a model of the geometricstructure. In certain embodiments of the present invention, the set ofrules are obtained from a central database over a communication network.The computer-aided design system typically includes an applicationprogram interface, and the instructions are typically communicated tothe computer-aided design system through the application programinterface.

The computer program typically includes means for producing a graphicaldisplay on a graphical user interface, including a first portionincluding information relating to the set of modeling rules and a secondportion including information from the computer-aided design system.This may involve directing a window display generated by thecomputer-aided design system to be displayed on the graphical userinterface. The display window can include a graphical representation ofthe geometric structure, and may also include controls for manipulatingthe graphical representation of the geometric structure.

In other embodiments of the present invention there is providedapparatus for computer-aided design modeling including means forgenerating instructions for modeling a geometric structure based on aset of modeling rules and means for communicating the instructions to acomputer-aided design system for generating a model of the geometricstructure.

In the various embodiments of the present invention, the set of rulescan include rules relating to both geometric and non-geometricattributes. Rules relating to non-geometric attributes can include, forexample, a rule for determine a cost of the geometric structure or arule for defining a process. The set of rules can include rules relatingto a class having a plurality of geometric structures. The set of rulescan include rules relating to geometric structures defined in thecomputer-aided design system.

Typical embodiments include a three-dimensional computer-aided designsystem controlled by a knowledge management system, such as theSOLIDWORKS™ three-dimensional computer-aided design system, and mayadditionally include a two-dimensional computer-aided design system,such as the VISIO™ two-dimensional computer-aided design system.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a block diagram showing an exemplary modeling system inaccordance with an embodiment of the present invention;

FIG. 2 is a block diagram showing the relevant components of theknowledge management system in accordance with an embodiment of thepresent invention;

FIG. 3A is a block diagram showing relevant components of the CAD systemin accordance with an embodiment of the present invention;

FIG. 3B is a block diagram showing the relevant components of a CADprogram in accordance with an embodiment of the present invention;

FIG. 4 is a block diagram showing an exemplary computer-aided modelingsystem in accordance with an embodiment of the present invention;

FIG. 5 shows an exemplary user interface screenshot for importinginformation from the CAD system relating to a mounting assembly, such asmight be generated by the knowledge management application in accordancewith an embodiment of the present invention;

FIG. 6 shows an exemplary user interface screenshot for defining a newgeometric specification relating to the Mounting part family, such asmight be generated by the knowledge management application in accordancewith an embodiment of the present invention;

FIG. 7 shows an exemplary user interface screenshot displayinginformation upon entry of the name of a new CAD part file, such as mightbe generated by the knowledge management application in accordance withan embodiment of the present invention;

FIG. 8 shows an exemplary user interface screenshot for defining ageometry feature, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention;

FIG. 9 shows an exemplary user interface screenshot showing geometryfeatures (properties) defined for the CAD part file, such as might begenerated by the knowledge management application in accordance with anembodiment of the present invention;

FIG. 10 shows an exemplary user interface screenshot for defining amating, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention;

FIG. 11 shows an exemplary user interface screenshot showing matingdefinitions, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention;

FIG. 12 shows an exemplary user interface screenshot showing a rule fordetermining a fan area for the fan, such as might be generated by theknowledge management application in accordance with an embodiment of thepresent invention;

FIG. 13 shows an exemplary user interface screenshot including anembedded graphical representation of a model generated by the CADsystem, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention;

FIG. 14 shows a first exemplary user interface screenshot including asub-window generated by the CAD system, such as might be generated bythe knowledge management application in accordance with an embodiment ofthe present invention;

FIG. 15 shows a second exemplary user interface screenshot including asub-window generated by the CAD system, such as might be generated bythe knowledge management application in accordance with an embodiment ofthe present invention;

FIG. 16 shows a third exemplary user interface screenshot including afull view window generated by the CAD system, such as might be generatedby the knowledge management application in accordance with an embodimentof the present invention;

FIG. 17 shows an exemplary user interface screenshot including a windowgenerated by a two-dimensional CAD system, such as might be generated bythe knowledge management application in accordance with an embodiment ofthe present invention;

FIG. 18 shows an exemplary user interface screenshot including ananalysis window, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention;

FIG. 19 shows the relationship between the user (engineer), knowledgemanagement application, knowledge database, and the integrated systemscontrolled by the knowledge management application in accordance with anembodiment of the present invention; and

FIG. 20 shows the relationship between the knowledge managementapplication and the integrated systems in greater detail;

FIG. 21 is a logic flow diagram showing exemplary logic for class-basedrules in accordance with an embodiment of the present invention; and

FIG. 22 is a logic flow diagram showing exemplary logic for theknowledge management application in accordance with an embodiment of thepresent invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

For the purpose of the present description, the attachments thereto, andthe accompanying claims, the following terms shall have the indicatedmeanings unless the context otherwise requires:

ActiveX Control—A reusable control written in Visual Basic used tocreate custom user interfaces in nAct.

Application—In the context of a model, a unit of deployment thatcontains one or more top-level parts and its components. In some cases,top-level part families can reference components in other applications.

Assembly—A grouping of parts and their subparts. An assembly is thehierarchy of parts that make up something meaningful to the engineers,such as a top-level part or a finished good.

Calculated Value—The value that was calculated by the formula that wasentered into the rules database. The formula may return a constant, acalculation based on other properties or a value obtained from acustomer database.

Check In/Check Out —

-   -   A project cannot be deleted if it contains line items that are        checked out to another user.    -   A line item cannot be deleted or edited if it is checked out to        another user.    -   A model cannot be edited if the line item is checked out to        another user.    -   When a user edits a model that is not checked out to anyone, the        corresponding line item automatically becomes checked out to        them.    -   Line items can be manually checked in or out by clicking the        Check In and Check Out buttons beneath the line item grid or by        clicking the corresponding options under the Line Item menu.        While editing a model automatically checks out a line item, the        check in process must always be done manually.    -   When a line item is checked out, Checked_Out_By column in the        LineItem table in the Project database is updated with the        user's username. When the line item is checked back in, the        column is set to null.    -   Anyone can edit a line item (or its model) if the line item is        not checked out to anyone.

Child Part Family—A family that inherits properties, subparts andconnections from another part family (template part family).

Code Generation—The creation of rules into executable source code foruse in nAct during run-time. The generated code can also be compiledinto a dynamic link library (.DLL) using Visual Basic.

Column—In an SQL table, the area in each row that stores the data valuefor some attribute of the object modeled by the table.

Compiled Mode—Editing models in nAct with rules that are compiled into aDLL file using Microsoft Visual Basic 6.0. In a typical embodiment ofthe invention, compiled rules cannot be seen by the user and cannot bedebugged at runtime. (See also Developer Mode)

Component—A component is any part or sub-assembly within an assembly.

Connection Collection—A conceptual or physical relationship between twoor more parts. This differs from a subpart collection in that the twoconnected parts do not have a parent-child relationship (such as a nutand a bolt).

Connection Constraint—The formula used to determine the correct part orparts to be connected at run-time. There is preferably never aconnection constraint associated with a connection specification wherethe same part family owns both.

Connection Point—A point in which two schematic shapes can be connecteddirectly or via wire.

Connection Spec—The definition of a relationship between two parts atrun-time (e.g. a hose and a valve). A connection exists when one part inan assembly needs to reference the properties of another part in anassembly and the user cannot or prefers not to walk up and down thepart/subpart hierarchy.

Constraint—A formula that indicates how a specification should becomputed in the design model.

Context—The current location of the part in the tree defined by itsparents, grandparents, etc. A part may be used in more than one locationin the tree, and each location is considered a different context.

Custom Control—A customer-developed ActiveX Control written in MicrosoftVisual Basic 6.0 and compiled to an .OCX file. Custom controls are usedto create custom interfaces for process steps.

Database—A collection of data arranged for ease and speed of search andretrieval. A database also includes an engine which accepts commandsfrom the user to insert, update, delete and select the data. Exemplaryembodiments of the invention use Microsoft SQL Server 2000 database tostore its data.

Decache—Resetting values based on a dependency.

Dependency—A property or attribute that is used in the calculation ofanother formula.

Design Time—Using nAct Expert to create part families and specifications(properties, subparts, connections, database constraints, geometry andschematics) and to write formulas for rules. (See also Run Time)

Developer Mode—Editing models in nAct with rules running in source codeusing Microsoft Visual Basic for Applications. The user can see theactual formulas for the rules and can step through and debug them at runtime. (See also Compiled Mode)

Display Name—This is a property that is used to create a formula-drivenname that appears in the run-time application instead of the part familypretty name. (Display Name can be placed on any part family.)

Drawing—A Drawing is a 2D representation of a 3D part or assembly.

Feature—A geometric attribute of a part (i.e. plane, extrusion, sketch,cut, etc.) whose dimensions can be driven by nAct properties within themodel.

Follow Part Number—When this flag is set, all parts with the same partnumber will share the user input value of its properties, subparts orconnections.

Frame—A component of a process step layout. Each layout contains 1 to 4frames. Each frame contains 1 of the following user interface elements:dynamically generated form, CAD system, 2D modeler, drawing, report orcustom control.

Hierarchy—A logical tree structure that organizes the members of adimension such that each member has one parent member and zero or morechild members.

IIS—Microsoft Internet Information Services. IIS includes a web server,SMTP (mail) services and FTP (file transfer protocol) services. TheRuleStream Enterprise Web tools must be installed on an IIS server. IISis a component of Microsoft Windows 2000 Server and Microsoft Windows2003 Server and can be installed from the Windows CD.

Index—In a relational database, a database object that provides fastaccess to data in the rows of a table, based on key values. Indexes canalso enforce uniqueness on the rows in a table. SQL Server supportsclustered and nonclustered indexes. The primary key of a table isautomatically indexed. In full-text search, a full-text index storesinformation about significant words and their location within a givencolumn.

Input Value—A value that is entered by the user in nact during run-time.This takes precedence over any calculated values.

Kernel—The knowledge engine that executes rules. It provides the basesystem functionality for managing the run-time model.

Layout—The configuration of the user interface of the model designerwindow in nAct. Each step in the selected process can have its ownunique layout. A layout consists of 1 to 4 frames, and each frame cancontain 1 of the following user interface elements: dynamicallygenerated form, CAD system, 2D modeler, drawing, report or customcontrol.

Line Item—A top-level part that is associated with a project. The lineitem has an associated top-level part family.

Local Constraint—A constraint owned the same part family as theassociated spec. This is the default formula.

Model—An actual design created using nact (the graphical representationof a line item).

nAct—The client server tool used to create projects, line items andmodels.

nAnswer—The web-based tool which allows users to query the databasesusing English like query statements.

nExplore—The web-based tool used to view rules and documentation.

nPlatform—The project and rules repository.

nQuality—The web-based tool for entering and reporting quality data,scoring and risks.

Override—The action of a higher-level part within an assemblydetermining the value for a subordinate part.

Owner Part Family—The part family that contains the specification orconstraint.

Parent Part Family—The part family that owns the subpart collection ofwhich the part is a member.

Part—An instance of a part family.

Part Family—The definition of a fundamental object in an assembly. Thismay be a component or a finished good.

Process—A defined set of steps. Each top-level part family can have 1 ormore processes. The processes that will be used during run time aredetermined by the line item definition.

Process Step—A defined workflow for editing a model during run time.Each process step has a layout that defines its user interface. Processsteps are grouped in categories and have a defined order within theprocess. Each process must have 1 or more process steps.

Property Constraint—The formula used to determine the value of aproperty.

Property Specification—The definition of the characteristics of a partfamily (e.g. height, weight, length).

Release—A snapshot of a model and its values.

Row—In an SQL table, the collection of elements that form a horizontalline in the table. Each row in the table represents a single occurrenceof the object modeled by the table and stores the values for all theattributes of that object.

Run Time—Using the nAct Model Designer to edit a model using definedpart families, specs and rules. Users design models in run time inCompiled Mode or Developer Mode. (See also Design Time)

Schematic—A 2D representation, usually associated with electricalcomponents.

Score—A value assigned to rate the effectiveness of the design.

Shape—A 2D object within a schematic diagram.

Specification—The constituent elements of a part family. Specificationsindicate that parts of that type always have certain properties, subpartcollections, or connection collections.

Step—(see Process Step)

Stored Procedure—A precompiled collection of Transact-SQL statementsstored under a name and processed as a unit.

Subpart Collection—A collection of component parts.

Subpart Link Constraint—The formulas used to determine existence, type,quantity and/or names of parts within the collection.

Subpart Link Spec—Provides the valid part families that can becomecomponents at run-time.

Subscription—The ability of one part family to assume the property,subpart or connection definitions and formulas of another part family.

Table—A two-dimensional object, consisting of rows and columns, used tostore data in a relational database. Each table stores information aboutone of the types of objects modeled by the database.

Template Part Family—The part family from which a child part familyinherits its characteristics.

UDF (User Defined Fields)—Customizable columns on the project table.There are four UDF columns available.

Unit—A unit of measure for a numeric property value. Like units aregrouped in unit categories. The unit category “Length” may include unitssuch as “feet”, “meters”, “inches” or “millimeters”.

VB—Microsoft Visual Basic 6.0. In exemplary embodiments of theinvention, Visual Basic is the language used to create custom controlsfor use in process steps and to create compiled versions of rules(application DLLs).

VBA—Microsoft Visual Basic for Applications.

View—A database object that can be referenced the same way as a table inSQL statements. Views are defined using a SELECT statement and areanalogous to an object that contains the result set of this statement.

Wire—A line or connector used when two connected objects are notcoincidental.

In embodiments of the present invention, a knowledge management systemcaptures, stores, manages, and applies rules for modeling geometricobjects and related non-geometric attributes. The knowledge managementsystem preferably supports rules relating to geometric attributes thatcan be represented and manipulated by a CAD system as well as rulesrelating to various other attributes that generally cannot berepresented and manipulated by the CAD system, such as certain“negative” geometric attributes (e.g., a specification for producing ahole in a component or for removing material from a component so as toform a feature of that component), certain geometry-based attributesthat are not modeled as physical features of a structure or assembly,and non-geometric attributes (e.g., pricing, processes, componentrelationships, component classes, user intentions, and abstractions).The rules are typically stored in a central database so that the rulescan be manipulated independently of any modeling. The rules can bederived from various sources, including general engineering principles,user-provided information, and information obtained from a PDM system.The knowledge management system can tracks rule changes over time, andcan apply a particular version of the rules to a model. The knowledgemanagement system defines the components and parameters for a particularmodel based on the rules being applied. The knowledge management systemcan incorporate predefined components (such as components created in aCAD system) or dynamically defined components into the model.

The knowledge management system is generally independent of the CADsystem, although the knowledge management system can interface with aCAD system for, among other things, importing/integrating componentspecifications from the CAD system for use in modeling, instructing theCAD system to produce a geometric model incorporating the components andparameters defined by the knowledge management system, and obtaininggeometric information relating to a model (e.g., sizes, surface areas,volumes) for use by the knowledge management system (e.g., for computingthe cost of a component based on its volume according to pricing rulesprovided by a user). A geometric model produced by the CAD system can beviewed and manipulated as usual using the CAD system, although it ispreferable for any and all changes to the model to be coordinatedthrough the knowledge management system so that the appropriate rulescan be applied to the changes.

In certain embodiments of the present invention, the knowledgemanagement system interfaces with the CAD system through an applicationprogram interface (API) of the CAD system. Specifically, the CAD systemincludes an API through which certain functions of the CAD system can beperformed. The CAD system API is typically used for such things asmacros (i.e., programs that perform a series of function steps for theuser) and add-ons (i.e., programs that add functionality to the CADsystem). In embodiments of the present invention, however, the knowledgemanagement system uses the API to control the CAD system such that theCAD system runs only when activated by the knowledge management system.The knowledge management system typically activates the CAD system forsuch things as displaying a model to the user and obtaining geometricinformation relating to model components.

FIG. 1 is a block diagram showing an exemplary modeling system 100 inaccordance with an embodiment of the present invention. Among otherthings, the modeling system 100 includes a knowledge management system110 in communication with a CAD system 120. The knowledge managementsystem 110 controls the CAD system 120, specifically by generatinginstructions for modeling a geometric structure based on a set ofmodeling rules and communicating the instructions to the computer-aideddesign system 120 for generating a model of the geometric structure. Theknowledge management system 110 can also interface with a CAEapplication 130 for analysis and with a PDM application 140 for productdocument management.

FIG. 2 is a block diagram showing the relevant components of theknowledge management system 110 in accordance with an embodiment of thepresent invention. Among other things, the knowledge management system110 includes a knowledge acquisition application 210 for capturing andgenerating rules, a knowledge storage application 220 for storing rulesand models in a central database 240, and a knowledge managementapplication 230 for generating models based on the rules. Among otherthings, the knowledge acquisition application 210 generates ruleprograms based on information obtained from a user and communicates therule programs to the knowledge storage application 220 for storage inthe central database 240. The knowledge management application 230obtains rule programs from the knowledge storage application 220 andapplies the rule programs for building a model. The knowledge managementapplication 230 may communicate model information to the knowledgestorage application 220 for storage in the central database 240.

More specifically, the knowledge acquisition application 210 capturesmodeling rules and generates rule programs for storage by the knowledgestorage application 220. The knowledge acquisition application 210interacts with a user through a user interface through which the userenters information regarding components, design processes, engineeringand manufacturing rules, and customer and marketing requirements. Theknowledge acquisition application 210 generates rule programs from theuser information, and sends the rule programs to the knowledge storageapplication 220 for storage. The knowledge acquisition application 210allows rules to be modified quickly and easily.

The knowledge storage application 220 stores modeling information in arelational database, including, among other things, rule programsgenerated by the knowledge acquisition application 210 and modelsgenerated by the knowledge management application 230. The knowledgestorage application 220 also tracks revision histories, design status,and user group security. Multiple revisions of a rule can be stored sothat a particular version of a rule can be applied to a model whileanother version of the rule is being created or modified. A design canbe modeled using an earlier version of a rule if desired.

The knowledge management application 230 applies rules to createdetailed computer models. The knowledge management application 230 canmodel two-dimensional schematics or three-dimensional geometries. Theknowledge management application 230 can also model a bill of materialsfor the components of an assembly. The knowledge management application230 can automatically update a previously completed model under revisedor new rules. In this way, models can be generated by manipulating therules through the knowledge management system rather than manipulatingthe model itself through the computer-aided design system.

FIG. 3A is a block diagram showing relevant components of the CAD system120 in accordance with an embodiment of the present invention. Amongother things, the CAD system 120 includes a 3D CAD program 301, such assuch as SOLIDWORKS™from SolidWorks Corporation, 300 Baker Avenue,Concord, Mass. 01742, and may also include a 2D CAD program 302, such asVISIO™ from Microsoft Corporation. Each of the CAD programs has its ownAPI through which it interacts with the knowledge managementapplication. FIG. 3B is a block diagram showing the relevant componentsof a CAD program, such as the 3D CAD program 301 or the 2D CAD program302, in accordance with an embodiment of the present invention. Amongother things, the CAD program includes a CAD application 320 having anAPI 310 through which certain functions of the CAD application 320 canbe controlled. The interactions between the knowledge managementapplication and different CAD systems depend to a large degree on theCAD system API. The SOLIDWORKS™ three-dimensional CAD program has aninternal macro/recording language and also supports an applicationprogramming interface language that is accessible through an OLE (ObjectLinking and Embedding) interface with support for VISUAL BASIC™ andVISUAL C++™. In an exemplary embodiment of the present invention, theknowledge management application is substantially reactive to the VISIO™two-dimensional CAD system, while the knowledge management applicationactively controls the SOLIDWORKS™ three-dimensional CAD system. Thus,support for each particular CAD system generally requires some level ofintegration by the knowledge management application to work with thespecific functions and API of the CAD program.

In certain embodiments of the present invention, the various functionsof the knowledge management system 110 are divided among differentdevices that communicate over a communication network, such as thepublic Internet or public or private intranets. In an exemplaryembodiment of the present invention, knowledge storage functions residein one or more storage servers that incorporate the knowledge storageapplication 220 and central database 240, while knowledge acquisitionand management functions reside in user workstations (such as personalcomputers) or terminals that incorporate the knowledge acquisitionapplication 210, the knowledge management application 230, and the CADsystem 120. The user workstations or terminals typically include a userinterface for interacting with a user and a network interface forcommunicating with the storage server over a communication network.

FIG. 4 is a block diagram showing an exemplary computer-aided modelingsystem in accordance with an embodiment of the present invention. Amongother things, the system 400 includes one or more user workstations 410in communication with one or more storage servers 430 over acommunication network 420. The workstation 410 incorporates theknowledge acquisition application 210, the knowledge managementapplication 230, and the CAD system 120, and also includes a userinterface for interacting with the user and a network interface forcommunicating over the communication network 420 with the storageserver(s) 430. The user interface 411 is typically a graphical userinterface that provides for both displaying information to the user andreceiving inputs from the user. The storage server 430 incorporates theknowledge storage application 220 and the central database 240, and alsoincludes a network interface 431 for communicating over thecommunication network 420 with the user workstation(s) 410.

Within the user workstation 410, the knowledge acquisition application210 and the knowledge management application 230 interact with the userthrough the user interface 411, and also interact with the knowledgestorage application 220 in the storage server 430 through the networkinterface 412 using a client-server paradigm. The knowledge managementapplication 230 also controls the CAD system 120 through an API of theCAD system 120. The user workstation 410 is typically a general-purposecomputer, and the knowledge acquisition application 210, the knowledgemanagement application 230, and the CAD system 120 are typicallysoftware programs that run on the general-purpose computer.

Within the storage server 430, the knowledge storage application 220interacts with the central database 240 through a database interface(not shown), and interacts with the knowledge acquisition application210 and the knowledge management application 230 in the user workstation410 through the network interface 431. The storage server 430 istypically a general-purpose computer, and the knowledge storageapplication 220 is typically a software program that runs on thegeneral-purpose computer. The central database 240 is typically arelational database.

FIG. 19 shows the relationship between the user (engineer) 1910,knowledge management application 1920, knowledge database 1930, and theintegrated systems 1940 controlled by the knowledge managementapplication 1920, including CAD system(s) and possibly also a CAEapplication, a PDM application, and a component databases. The knowledgemanagement application 1920 extracts rules for design automation fromthe knowledge database 1930. The knowledge management application 1920may also receive specifications, rules, and other information relatingto modeling. A product control modeler element of the knowledgemanagement application 1920 interacts with the integrated applicationsas necessary for modeling, analysis, product document management, andcomponent selection. Information generated by the knowledge managementapplication 1920, such as runtime rule authoring and trend analysis, maybe stored in the knowledge database 1930.

FIG. 20 shows the relationship between the knowledge managementapplication and the integrated systems in greater detail. The knowledgemanagement application 1920 interacts with the CAD system 2010 formodeling such things as features, mating conditions, surface area,volume, and mass properties. The knowledge management application 1920interacts with the CAE analysis application 2020 for such things asstress, thermal, kinematics, and loads analysis. The knowledgemanagement application 1920 interacts with the PDM application 2030 togenerate and utilize such things as files, structure, workflow, and billof materials (BOM). The knowledge management application 1920 interactswith component databases 2040 for such things as part numbers,standards, inventory, and pricing.

In typical embodiments of the present invention, a model may includemultiple geometric components. Each component can be associated withboth geometric attributes and non-geometric attributes. Rules can beestablished for defining relationships between components withoutnecessarily defining that actual parameters of the relationship (suchas, for example, a rule that a fan blade assembly must mate with a motorshaft, without necessarily defining the shape or size of the shaft whichmight affect the type of mating). Components can be organized intoclasses (such as, for example, three possible motors for a fan assemblycan be organized into a “motors” class), and rules can be establishedfor the class as a whole such that the rules are applied to whateverclass member is selected for inclusion in a particular model (such as,for example, a generic rule that any of the class of motors must matewith a fan blade component). Rules can be established for selecting aparticular member of a class for a particular model (such as, forexample, a rule for selecting a particular motor based on the amount ofpower or the rotational speed required for a model, or a rule forselecting the number of fan blades for the fan blade component based onthe volume of air to be moved and other parameters such as the motorselected and the diameter of the fan blade component). Rules relating to“negative” attributes can be defined (such as, for example, a rule thata motor frame must include a hole in a particular location for boltingthe motor frame to a chassis) and applied to a model component as alibrary feature. Rules relating to various non-geometric attributes canbe established (such as, for example, rules for deriving manufacturingprocesses based on the components incorporated into a selected model, orrules for estimating component, sub-assembly, product, and manufacturingcosts).

One particular implementation of a knowledge management application inaccordance with an embodiment of the present invention is described inAttachment I (consisting of numbered pages 1-91) and in Attachment II(consisting of numbered pages 1-113), each of which is herebyincorporated herein by reference in its entirety. Within theseattachments, the knowledge management system may be referred togenerally as “Rulestream” or “Navion,” the knowledge managementapplication may be referred to as “nAct” or “nAct Engineer,” theknowledge acquisition application may be referred to as “nAct Expert,”and the knowledge storage application may be referred to as “nPlatform.”In Attachment II, edit rules relating to “Geometry Specification” and“Geometry Constraint” generally relate to the SOLIDWORKS™three-dimensional CAD system, while edit rules relating to “2DSchematicSpecification” generally relate to the VISIO™ two-dimensional CADsystem.

As discussed above, the knowledge management application controls theCAD system through a CAD system API. While the actual CAD functions thatcan be performed through the API are substantially limited by the API(and are subject to change by the CAD system provider), the specific APIfunctions used and the manner in which the API functions are used aredetermined by the knowledge management application for performingspecific knowledge management operations. In an exemplary embodiment ofthe present invention, the knowledge management application controls theSOLIDWORKS™ three-dimensional CAD system through its API. In order tocontrol the CAD system, the knowledge management application typicallyperforms such operations as starting SOLIDWORKS™, opening a part file,opening an assembly file, mating a component, deleting a mate, fixing acomponent, removing a part or assembly, suppressing a component,hiding/showing a component, suppressing a feature, inserting a libraryfeature, removing a library feature, setting a part dimension, settingan assembly dimension, creating a component pattern, removing acomponent pattern, creating a feature pattern, removing a point in asketch, removing a feature pattern, setting a custom property, settingcomponent color, and closing SOLIDWORKS™. This is not meant as anexhaustive list, and the knowledge management application can performother operations as needed. Exemplary API calls and settings forperforming the above operations in an exemplary embodiment of theinvention are described below.

Starting SOLIDWORKS™ may involve use of the following API functions:

-   -   Set SW=New SldWorks.SldWorks    -   SW.UserControl=False    -   Set Assembly=SW.OpenDoc6(strFilename, swDocPART,        -   swOpenDocOptions_Silent, “ ”, lngErr, lngMess)

The following SOLIDWORKS™ settings may be used:

-   -   swMateAnimationSpeed=0    -   swLargeAsmModeAutoActivate=swResponseNever    -   swPerformanceAssemRebuildOnLoad=swResponseAlways    -   swLoadExternalReferences=swResponseNever    -   swAutoSaveInterval=0    -   swBackupCopiesPerDocument=0    -   swShowErrorsEveryRebuild=False    -   swMaximizeDocumentOnOpen=True    -   swSnapToPoints=False    -   swLargeAsmModeAutoLoadLightweight=False    -   swLargeAsmModeUpdateMassPropsOnSave=False    -   swLargeAsmModeAutoRecover=False    -   swAutoLoadPartsLightweight=False    -   swPerformanceVerifyOnRebuild=False    -   swEnablePerformanceEmail=False    -   swUseFolderSearchRules=False    -   swExtRefUpdateCompNames=True    -   swFeatureManagerEnsureVisible=False

Opening a part file typically involves opening the part file, adding thepart file as a component to a parent assembly, closing the part file,and rebuilding the top level assembly. The following API functions maybe used:

-   -   Set objDoc=SW.OpenDoc6(strFilename, swDocPART,        swOpenDocOptions_Silent, “ ”, lngErr, lngMess)    -   Assembly.AddComponent2(strFilename, 0, 0, 0)    -   SW.CloseDoc objDoc.GetTitle    -   Assembly.EditRebuild3

Opening an assembly file typically involves opening the part file,adding the part file as a component to a parent assembly, closing thepart file, and rebuilding the top level assembly. If assembly dimensionsare driven by the knowledge management application, then all componentsare typically renamed to ensure uniqueness. The following API functionsmay be used:

-   -   Set objDoc=SW.OpenDoc6(strFilename, swDocPART,        swOpenDocOptions_Silent, “ ”, lngErr, lngMess)    -   Set objconfiguration=objDoc.GetActiveConfigurationO    -   Set obj Component=objConfiguration.GetRootComponent( )    -   objComponent.GetChildren    -   Set objChildDoc=objChild.GetModelDoc objChildDoc.SaveAs4        strNewFileName swSaveAsCurrentVersion, swSaveAsOptions_Silent,        lngErr, lngWarnings    -   SWAssembly.AddComponent2(strFilename, 0, 0, 0)    -   SW.CloseDoc objDoc.GetTitle    -   SWAssembly.EditRebuild3

Mating a component typically involves putting the parent assembly in“edit” mode, selecting the features to mate, adding the mate, andrebuilding the assembly. The mate name is then found and noted by theknowledge management application in the case where a dependent propertyis changed and the mating is effected. The following API functions maybe used:

-   -   ObjParentComponent.Select False    -   Assembly.EditAssembly

Selecting Plane, Axis, or Point

-   -   Assembly.SelectByID strFeatureName, strFeatureType, 0, 0, 0        (also used, strFeatureName & “@,” & strComponentPath, and        “Point1@” & strFeatureName) Selecting Face or Edge (loop through        Faces, or Faces and Edges to find name match)    -   objComponent.GetBody( ), objBody.GetFirstFaceo,        -   objBody.GetNextFace( ), objFace.GetEdges,        -   Assembly.GetEntityName(obj)    -   Assembly.AddMate lngMateType, lngAlignType, boolFlip, dblDist,        dblAngle    -   Assembly.EditRebuild3

Finding the Mate created (find the MateGroup, move to the lastSubFeature)

-   -   Assembly.FeatureByPositionReverse(i)    -   objFeature.GetTypeName=“MateGroup”    -   objMateGroup.GetFirstSubFeature    -   objMate.GetNextSubFeatureO

Deleting a mate typically involves selecting the mate using the parentassembly's model document and deleting the selection. The following APIfunctions may be used:

-   -   Assembly.SelectByID strMateName, “MATE”, 0, 0, 0    -   Assembly.DeleteSelection False    -   Assembly.EditRebuild3

Fixing a component typically involves setting the component transform,selecting the component, and fixing the component. The following APIfunctions may be used:

-   -   objComponent.GetXform    -   objComponent.SetXform (varXForm)    -   objComponent.Select False    -   Assembly.FixComponent    -   Assembly.EditRebuild3

Removing a part or assembly typically involves selecting the parentassembly, putting the parent assembly in “edit” mode, selecting thecomponent, and deleting the selection. The following API functions maybe used:

-   -   objParentComp.Select False    -   Assembly.EditAssembly    -   objComponent.Select False    -   Assembly.DeleteSelection False    -   Assembly.ClearSelection    -   Assembly.EditAssembly    -   Assembly.EditRebuild3

Suppressing a component typically involves checking the suppressionstate of the component and setting the suppression state, if suppressingthe document is saved. The following API functions may be used:

-   -   objComponent.IsSuppressed    -   Set oModelDoc=objComponent.GetModelDoc    -   oModelDoc.Save3 swSaveAsOptions_Silent, lngErr, lngwarnings    -   objComponent.Select False    -   Assembly.EditSuppress2 or Assembly.EditUnSuppress2    -   Assembly.EditRebuild3

Hiding or showing a component typically involves setting the hiddenstate appropriately. The following API functions may be used:

-   -   objComponent.IsHidden(False)    -   objComponent.Select False    -   Assembly.ShowComponent2, Assembly.HideComponent2    -   Assembly.EditRebuild3

Suppressing a feature typically involves traversing the model documentsto find the named feature and setting its suppression state accordingly.The following API functions may be used:

-   -   objModelDoc.FirstFeature    -   objFeature.Name( )    -   objFeature.GetNextFeature( )    -   objFeature.IsSuppressed    -   objFeature.SetSuppression 0    -   objFeature.SetSuppression 2

Inserting a library feature typically involves selecting the componentto receive the feature, putting the component in “edit” mode, selectingthe references required for insertion, and inserting the libraryfeature. The new feature and its sub-features are typically renamed. Thefollowing API functions may be used:

-   -   objParentComponent.Select2 False, 0    -   Assembly.EditPart2 True, True, lngErr    -   obj.Select2 True, intMark (Traverse features and select for        Edges and Faces)    -   Assembly.AndSelectByMark(strFeatureName & “@” &        strComponentPath, strFeatureType, 0, 0, 0, intMark) (Plane,        Point, or Axis)    -   Assembly.InsertLibraryFeature(strFileName)    -   Assembly.SelectedFeatureProperties 0, 0, 0, 0, 0, 0, 0, 1, 0,        strNewName)    -   objFeature.GetFirstSubFeature, subFeature.Name( ),        -   subFeature.GetNextFeature( )    -   Assembly.EditAssembly    -   Assembly.EditRebuild3

Removing a library feature typically involves selecting component owningthe feature, putting the component in “edit” mode, selecting thefeature, and deleting the feature using the context of the top levelassembly. The following API functions may be used:

-   -   objComponent.Select2 False, 0    -   Assembly.EditPart2 True, True, lngErr    -   Assembly.ClearSelection    -   Assembly.SelectByID strFeatureName & “@” & objComponentPath,        -   “BODYFEATURE”, 0, 0, 0    -   Assembly.DeleteSelection False    -   Assembly.EditAssembly    -   Assembly.EditRebuild3

Setting a part dimension typically involves setting the read-only statusof the dimension to false, setting the system value for the dimension,and resetting the read-only status of the dimension to true (this isbecause all dimensions controlled by the knowledge managementapplication are preferably maintained as read-only to preventmodification through the CAD system). A dimension is typicallyreferences by a string (e.g. D1@Sketch1). The following API functionsmay be used:

-   -   objDoc.Parameter(strDimension).ReadOnly=False    -   objDoc.Parameter(strDimension).SystemValue=varValue    -   objDoc.Parameter(strDimension).ReadOnly=True

Setting an assembly dimension typically involves all of the steps forsetting an assembly dimension, except Parameter is additionally checkedfor existence on the components. The following API functions may beused:

-   -   objDoc.Parameter(strDimension & “@” &        strComponent).ReadOnly=False    -   objDoc.Parameter(strDimension & “@” &        strComponent).SystemValue=varValue    -   objDoc.Parameter(strDimension & “@” &        strComponent).ReadOnly=True OR    -   objDoc.Parameter(strDimension & “@” & strComponent &        “.Part”).ReadOnly=False    -   objDoc.Parameter(strDimension & “@” & strComponent &        “.Part”).SystemValue=varValue    -   objDoc.Parameter(strDimension & “@” & strComponent &        “.Part”).ReadOnly=True OR    -   objDoc.Parameter(strDimension & “@” & strComponent &        “.Assembly”).ReadOnly=False    -   objDoc.Parameter(strDimension & “@” & strComponent &        “.Assembly”).SystemValue=varValue    -   objDoc.Parameter(strDimension & “@” & strComponent &        “.Assembly”).ReadOnly=True

Creating a component pattern typically involves selecting the parentassembly, putting the parent assembly in “edit” mode, selecting thecomponent and the feature pattern, and inserting the feature pattern.The Derived Pattern is typically renamed by traversing the parentassembly and finding the Derived Pattern using the seed component. Thefollowing API functions may be used:

-   -   objComponent.Select False    -   Assembly.EditAssembly    -   Assembly.ClearSelection    -   Assembly.SelectByID strComponentPath, “COMPONENT”, 0, 0, 0    -   Assembly.AndSelectByID strPatternName & “@” & strComponentPath2,        “BODYFEATURE”, 0, 0, 0    -   Assembly.InsertDerivedPattern    -   Set objFeature=objDoc.FirstFeature    -   objFeature.GetTypeName=“DerivedSketchPattern”    -   arrSeed=def.SeedComponentArray( )    -   arrSeed(i).Name    -   def.ReleaseSelectionAccess    -   Set objFeature=objFeature.GetNextFeature

Removing a component pattern typically involves selecting the DerivedPattern from the parent model document and deleting the selection. Insome models, the referenced configuration may need to be reset toprevent future selections from failing on this part. The following APIfunctions may be used:

-   -   oParentDoc.ClearSelection    -   oParentDoc.SelectByID strPatternName, “COMPPATTERN”, 0, 0, 0    -   oParentDoc.DeleteSelection False    -   oParentComponent.ReferencedConfiguration=    -   Assembly.EditRebuild3

The knowledge management application typically requires a part for eachfeature in the pattern, and maintains a property containing the X and Ycoordinates for each feature. In order to create a feature pattern, theis activated and is used to select the Sketch Pattern. A point for eachcomponent required is created, it's identifier is stored, the Sketch isinserted, and the document rebuilt. The Sketch and Feature are selectedand a Pattern is created. The Sketch Pattern is then found and renamedby traversing the Document and finding the Pattern using the seedfeature. The following API functions may be used:

-   -   SW.ActivateDoc2 objDoc.GetTitle, True, lngErr    -   objDoc.ClearSelection    -   objDoc.SelectByID strSketchName, “SKETCH”, 0, 0, 0    -   objDoc.SetAddToDB True    -   objDoc.EditSketch    -   Set oPoint=objDoc.CreatePoint2(lngX, lngY, 0)    -   arrPointID=oPoint.GetId( )    -   objDoc.InsertSketch    -   objDoc.EditRebuild3    -   objDoc.SelectByID strSketch, “SKETCH”, 0, 0, 0    -   objDoc.AndSelectByID strFeature, “BODYFEATURE”, 0, 0, 0    -   objDoc.ActivateSelectedFeature    -   objDoc.FeatureSketchDrivenPattern 1    -   Set objFeature=objDoc.FirstFeature    -   objFeature.GetTypeName=“SketchPattern”    -   arrSeed=def.PatternFeatureArray( )    -   Set subFeature=arrSeed(i)    -   objModelDoc.GetEntityName(subFeature)=strSeedName    -   def.ReleaseSelectionAccess    -   Set objFeature=objFeature.GetNextFeature    -   SW.ActivateDoc2 Assembly.GetTitle, True, lngErr    -   SW.CloseDoc objDoc.GetTitle

Removing a point in a sketch typically involves opening the documentcontaining the sketch, putting the sketch in “edit” mode, traversing thesketch points to find the point with the corresponding identifier,selecting the point, and deleting the selected point. The following APIfunctions may be used:

-   -   SW.ActivateDoc2 objDoc.GetTitle, True, lngErr    -   objDoc.ClearSelection    -   objDoc.SelectByID strSketchName, “SKETCH”, 0, 0, 0    -   objDoc.EditSketch    -   Set oSketch=objModelDoc.GetActiveSketch2( )    -   arrPoints=oSketch.GetSketchPoints    -   arrID=arrPoints(i).GetId    -   arrPoints(i).Select2 False, 0    -   objDoc.DeleteSelection False    -   objDoc.InsertSketch    -   objDoc.EditRebuild3    -   SW.ActivateDoc2 Assembly.GetTitle, True, lngErr    -   SW.CloseDoc objDoc.GetTitle

Removing a feature pattern typically involves selecting the derivedpattern from the parent model document and deleting the selected derivedpattern. The following API functions may be used:

-   -   oParentDoc.ClearSelection    -   oParentDoc.SelectByID strPatternName, “BODYFEATURE”, 0, 0, 0    -   oParentDoc.DeleteSelection False    -   Assembly.EditRebuild3

Setting a custom property typically involves verifying the value andsetting the value if necessary. The following API functions may be used:

-   -   objDoc.GetCustominfoValue(“ ”, strName) ovarArgument    -   objDoc.CustomInfo2(“ ”, strName)=varArgument    -   Assembly.EditRebuild 3

Setting a component color typically involves retrieving theMaterialPropertyValues for the component from the component or the modeldocument, changing the first three elements in the array to reflect thenew color, and setting the new MaterialPropertyValues on the component.If the color is being removed, the RemoveMaterialProperty is called. Thefollowing API functions may be used:

-   -   arr=objComponent.MaterialPropertyValues( )    -   arr=objComponent.GetModelDoc.MaterialPropertyValues( )    -   objComponent.MaterialPropertyValues=arr    -   Assembly.EditRebuild 3    -   objComponent.RemoveMaterialProperty

Closing SOLIDWORKS™ typically involves closing the top level assembly(which is typically the only one open at this point) and calling theExit App API function.

The following API functions may be used:

-   -   SW.QuitDoc strTitle    -   SW.ExitApp

Various aspects of an exemplary embodiment of the present invention aredescribed hereinafter with reference to modeling a fan. In accordancewith an embodiment of the present invention, a fan includes varioussub-parts, including a fan assembly, a housing assembly, a motorassembly, and a mounting assembly. Certain components of the fan mighthave fixed characteristics. For example, a company might purchase threedifferent motors that can be used in a fan, and these motors have fixeddimensions that cannot be changed in the model. CAD models of the motorsmay be created in the CAD system and imported into the knowledgemanagement application for storage by the knowledge storage application.Other components of the fan might have characteristics that can bedetermined dynamically during modeling. For example, the dimensions of afan hub might depend on the motor selected for the model. Models ofthese components might be created in the CAD system and imported intothe knowledge management application, or rules for defining thesecomponents might be established. For purposes of the following example,the CAD system is presumed to be the SOLIDWORKS™ three-dimensional CADsystem.

FIG. 5 shows an exemplary user interface screenshot 500 for importinginformation from the CAD system relating to a mounting assembly, such asmight be generated by the knowledge management application in accordancewith an embodiment of the present invention. The screenshot 500displays, among other things, a hierarchical part family tree 510showing that a BuildingServicesFan part family includes sub-partsentitled FanAssembly, HousingAssembly, MotorAssembly, andMountingAssembly, with the sub-parts having their own part familiesentitled Rotor, Housing, Motor, and Mounting, respectively. Thescreenshot 500 shows information relating to the MountingAssemblysub-part (as indicated by the MountingAssembly sub-part beinghighlighted in the part family tree 510), including a list of allspecifications 520 relating to the MountingAssembly sub-part and awindow 530 for entering information about the MountingAssembly sub-part.The screenshot 500 also includes a toolbar 540 from which variousfunctions of the knowledge management application (such as creating anew part family, sub-part, property, connection, or CAD specification)can be accessed using either pull-down menus or icons. The window 530includes a portion 531 showing that there is a single valid part familyentitled Mounting associated with the MountingAssembly sub-part. Itshould be noted that there could be multiple part families associatedwith the MountingAssembly sub-part, and all valid part families would bedisplayed in the portion 531. The window 530 also includes a portion 532for defining a rule to determine the optimal part family for aparticular model (in this case, the optimal part family is the Mountingpart family by default).

In order to associate a mounting component defined in the CAD systemwith the Mounting part family, the user might highlight “Mounting” inthe part family tree 510 and then select a function from the toolbar 540to create a new geometric specification (this function can be accessedfrom either the File menu or an icon on the toolbar). FIG. 6 shows anexemplary user interface screenshot 600 for defining a new geometricspecification relating to the Mounting part family, such as might begenerated by the knowledge management application in accordance with anembodiment of the present invention. The screenshot 600 showsinformation relating to the Mounting part family of the MountingAssemblysub-part (as indicated by the Mounting part family being highlighted inthe part family tree 610), including a list of all specifications 620relating to the Mounting part family and a window 630 for entering thenew geometric specification for the Mounting part family. The window 630shows the geometry type 631 (in this case, “SolidWorks”) and a list ofvalid CAD part files 632 associated with the Mounting part family (inthis case, none have yet been specified).

In order to associate a CAD part file with the Mounting part family, theuser might select the “add part file” control 633 and enter the name ofa CAD part file, in which case the knowledge management applicationimports from the CAD system information relating to the specified CADpart file. The knowledge management application preferably displays alist of parameters defined for the part in the CAD part file. FIG. 7shows an exemplary user interface screenshot 700 displaying informationupon entry of the name of a new CAD part file, such as might begenerated by the knowledge management application in accordance with anembodiment of the present invention. The screenshot 700 shows the partfamily tree 710, a list of all specifications 720 relating to theMounting part family, a window 730 showing the new valid part file(Mounting-Aero.SLDPR), and a window 740 displaying a list of parametersdefined for the part in the CAD part file.

Once the CAD part file has been associated with the Mounting partfamily, the user typically defines various geometry features andassociates the geometry features with specific CAD parts. In order todefine a geometry feature and associate the geometry feature with one ormore specific CAD parts, the user might select a function from thetoolbar 750 to create a new geometry feature (this function can beaccessed from either the File menu or an icon on the toolbar). FIG. 8shows an exemplary user interface screenshot 800 for defining a geometryfeature, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention.The screenshot 800 includes a window 840 for defining a geometry featureand associating the geometry feature with one or more specific CADparts. In this case, a geometry feature having a display name 842HubDiameter and a system name HubDiameter 843 is associated with acorresponding CAD part entitled HubDiameter by specifying a formula inportion 844.

FIG. 9 shows an exemplary user interface screenshot 900 showing geometryfeatures (properties) defined for the CAD part file, such as might begenerated by the knowledge management application in accordance with anembodiment of the present invention. The screenshot 900 shows the partfamily tree 910, a list of all specifications 920 relating to theMounting part family, and a window 930 including a properties portion931 showing the geometry features associated with specific CAD parts (inthis case, a HubDiameter geometry feature and a MountingDiametergeometry feature).

After the geometry features have been defined and associated withcorresponding CAD parts, the user typically defines any mating rulesassociated with the CAD parts file. In order to define a mating, theuser may select a function from the toolbar 950 (this function can beaccessed from either the File menu or an icon on the toolbar). FIG. 10shows an exemplary user interface screenshot 1000 for defining a mating,such as might be generated by the knowledge management application inaccordance with an embodiment of the present invention. The screenshot1000 shows the part family tree 1010, a list of all specifications 1020relating to the Mounting part family, a part file window 1030, and awindow 1040 for entering mating information.

FIG. 11 shows an exemplary user interface screenshot 1100 showing matingdefinitions, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention.The screenshot 1100 shows the part family tree 1110, a list of allspecifications 1120 relating to the Mounting part family, and a window1130 displaying various mating (orientation) definitions 1131 for theCAD part.

As discussed above, the user can establish rules for attributes that maybe difficult or impossible to model in the CAD system, including certaingeometric attributes (such as “negative” attributes), certaingeometry-based attributes that are not modeled as physical features of astructure or assembly, and non-geometric attributes (such as pricing andprocesses). For example, continuing with the fan modeling scenarioabove, it might be useful to establish a rule for computing anon-modeled geometry-based attribute, such as area covered by the sweepof the fan blade component when rotating. While this fan area might beuseful, for example, for computing the volume of air moved by a fanblade component having a specified number of blades rotating at aspecified rate, the fan area is typically not modeled as a physicalfeature of the fan. FIG. 12 shows an exemplary user interface screenshot1200 showing a rule for determining a fan area for the fan, such asmight be generated by the knowledge management application in accordancewith an embodiment of the present invention. The screenshot 1200 showsthe part family tree 1210 (with the part family BuildingServicesFanhighlighted), a list of all specifications 1220 relating to theBuildingServicesFan part family (with the FanArea specificationhighlighted), and a window 1230 displaying the rule 1240 for determiningthe fan area based on the diameter of the fan blade component. The usercan establish other rules that utilize this FanArea value.

After component information has been imported from the CAD system andmodeling rules have been established, the knowledge managementapplication controls the CAD system through its API to produce ageometric model according to predetermined specifications. Thespecifications can be incorporated into the rules and/or provided by auser at run time. The CAD model may be produced for display to the uservia the graphical user interface, or may be produced solely for theknowledge management application to obtain model-related informationfrom the CAD system. As an example of the former, the knowledgemanagement application can control the CAD system to generate a modeland then produce a graphical display through the graphical userinterface including a graphical representation of the model as generatedby the CAD system (e.g., by displaying a display window generated by thecomputer-aided design system), with or without related information fromthe knowledge management system. As an example of the latter, theknowledge management application can control the CAD system to generatea model and then control the CAD system to compute the surface area of acomponent for a cost estimate to be produced by the knowledge managementapplication.

FIG. 13 shows an exemplary user interface screenshot 1300 including anembedded graphical representation of a model generated by the CADsystem, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention.The screenshot 1300 shows the part family tree 1310 (with the partfamily BuildingServicesFan highlighted), a list of all specifications1320 relating to the BuildingServicesFan part family, and a window 1330including a portion 1340 including a graphical representation of themodel generated by the CAD system.

The user can specify how information is to be displayed by the knowledgemanagement application. For example, the user can specify that the CADsystem window be displayed under some conditions but not others, and canalso specify what knowledge management system information to displayalong with the CAD system window.

FIG. 14 shows a first exemplary user interface screenshot 1400 includinga sub-window generated by the CAD system, such as might be generated bythe knowledge management application in accordance with an embodiment ofthe present invention. The screenshot 1400 displays a function list1410, information from the knowledge management system 1430, and asub-window 1440 generated by the CAD system including a graphicalrepresentation of the model generated by the CAD system and controls formanipulating the model.

FIG. 15 shows a second exemplary user interface screenshot 1500including a sub-window generated by the CAD system, such as might begenerated by the knowledge management application in accordance with anembodiment of the present invention. The screenshot 1500 displays afunction list 1510, a part family tree 1520, information from theknowledge management system 1530, a sub-window 1540 generated by the CADsystem including a graphical representation of the model generated bythe CAD system and controls for manipulating the model, and propertiesinformation 1550.

FIG. 16 shows a third exemplary user interface screenshot 1600 includinga full view window generated by the CAD system, such as might begenerated by the knowledge management application in accordance with anembodiment of the present invention. The screenshot 1600 displays afunction list 1610 and a full view window 1630 generated by the CADsystem.

In certain embodiments of the invention, the user can make rule changeson the fly, and the knowledge management application will control theCAD system to update the model accordingly and will display the updatedgraphical representation of the model to the user substantially in realtime. In this way, the user essentially gets immediate feedbackregarding the rule change.

In certain embodiments of the invention, changes to a model can be madein the CAD system, and the knowledge management application willidentify those changes through interactions with the CAD system and willmodify and apply rules accordingly. For example, if the user makes achange in the CAD system that overrides a particular rule, the knowledgemanagement application might cause appropriate tracking information tobe stored by the knowledge storage application, create one or morerevised rules that reflect the change, and apply other rules to updateother components of the model according to the rules. The manner inwhich the knowledge management application can identify CAD systemchanges depends to a large degree on the CAD system API. For example,the CAD system might communicate the changes to the knowledge managementapplication, or the knowledge management application might monitor orpoll the CAD system for changes.

In certain embodiments of the invention, the knowledge managementapplication can cause a particular model part displayed in the CADsystem window to be displayed or highlighted when the user is working onrules relating to that part. For example, with reference again to FIG.13, if the user selects the Motor part family in the part family tree1310, the knowledge management application might cause the motor to behighlighted in the window 1340, for example, by changing the color ofthe motor.

In certain embodiments of the invention, the knowledge managementapplication can cause information relating to a particular model part tobe displayed when the user highlights that part in the CAD systemwindow. For example, with reference again to FIG. 13, if the userhighlights the fan blade component in the CAD window 1340, the knowledgemanagement application might cause information relating to the fan bladecomponent to be displayed in the window 1330, with appropriatehighlighting in the part family tree 1310 and the list of specifications1320.

As discussed above, the knowledge management application caninteroperate with two-dimensional CAD systems as well asthree-dimensional CAD systems. In an exemplary embodiment of the presentinvention, the knowledge management application supports both thetwo-dimensional CAD system VISIO™ and the three-dimensional CAD systemSOLIDWORKS™.

FIG. 17 shows an exemplary user interface screenshot 1700 including awindow generated by a two-dimensional CAD system, such as might begenerated by the knowledge management application in accordance with anembodiment of the present invention. The screenshot 1700 displays afunction list 1710, a part family tree 1720, a CAD system window 1740,and properties information 1750.

The knowledge management application can also interoperate with variousanalysis applications. Typically, the knowledge management applicationexports information to the analysis application for analysis. Theknowledge management application can display analysis information to theuser.

FIG. 18 shows an exemplary user interface screenshot 1800 including ananalysis window, such as might be generated by the knowledge managementapplication in accordance with an embodiment of the present invention.The screenshot 1800 displays a function list 1810, a part family tree1820, a CAD system window 1840, properties information 1850, and ananalysis window 1860 generated by the analysis application.

Thus, in certain embodiments of the present invention, structures aredefined in a CAD system and are associated with a structure class. Rulesare defined for the structure class. When one of the structures isselected by the knowledge management system for a computer-aided designmodel, the rules are applied to the selected structure. Theseclass-based rules make it easier for the user to define rules, since asingle rule defined by the user gets applied to an entire class ofstructures, and therefore the user does not have to define the ruleindividually for each structure of the structure class.

FIG. 21 is a logic flow diagram showing exemplary logic 2100 forclass-based rules in accordance with an embodiment of the presentinvention. Starting in block 2102, structures (such as parts for anassembly) are defined in a CAD system, in block 2104. The structures areassociated with a structure class (such as a part family) in a knowledgemanagement system, in block 2106. At least one rule is defined thatapplies to the structure class, in block 2108. When one of thestructures is selected for a computer-aided design model by theknowledge management system, in block 2110, the knowledge managementsystem applies the rule(s) to the selected structure, in block 2112. Thelogic 2100 ends in block 2199.

As discussed above, the knowledge management application obtains a setof rules from a central database. The set of rules may include rulesrelating to geometric and non-geometric attributes. The non-geometricattributes may be dependent on geometric attributes. The knowledgemanagement application generates instructions for modeling a geometricstructure based on the set of rules. The knowledge managementapplication communicates the instructions to a computer-aided designsystem, typically through an API of the computer-aided design system.The knowledge management application may produce a graphical display ona graphical user interface including information from the knowledgemanagement system as well as information from the computer-aided designsystem (such as a graphical representation of a geometric model).

FIG. 22 is a logic flow diagram showing exemplary logic 2200 for theknowledge management application in accordance with an embodiment of thepresent invention. Starting in block 2202, the logic obtains a set ofrules from a central database, in block 2204. The logic generatesinstructions for modeling a geometric structure based on the set ofrules, in block 2206. The logic communicates the instructions to acomputer-aided design system, in block 2208, typically through anapplication program interface of the computer-aided design system. Thelogic may produce a graphical display on a graphical user interfaceincluding a first portion including information from the knowledgemanagement application and a second portion including information fromthe computer-aided design system, in block 2210. The logic ends in block2299.

It should be noted that the logic flow diagrams are used herein todemonstrate various aspects of the invention, and should not beconstrued to limit the present invention to any particular logic flow orlogic implementation. The described logic may be partitioned intodifferent logic blocks (e.g., programs, modules, functions, orsubroutines) without changing the overall results or otherwise departingfrom the true scope of the invention. Often times, logic elements may beadded, modified, omitted, performed in a different order, or implementedusing different logic constructs (e.g., logic gates, looping primitives,conditional logic, and other logic constructs) without changing theoverall results or otherwise departing from the true scope of theinvention.

The present invention may be embodied in many different forms,including, but in no way limited to, computer program logic for use witha processor (e.g., a microprocessor, microcontroller, digital signalprocessor, or general purpose computer), programmable logic for use witha programmable logic device (e.g., a Field Programmable Gate Array(FPGA) or other PLD), discrete components, integrated circuitry (e.g.,an Application Specific Integrated Circuit (ASIC)), or any other meansincluding any combination thereof. In a typical embodiment of thepresent invention, predominantly all of the knowledge management systemapplications are implemented as a set of computer program instructionsthat are executed by a computer under the control of an operatingsystem.

Computer program logic implementing all or part of the functionalitypreviously described herein may be embodied in various forms, including,but in no way limited to, a source code form, a computer executableform, and various intermediate forms (e.g., forms generated by anassembler, compiler, linker, or locator). Source code may include aseries of computer program instructions implemented in any of variousprogramming languages (e.g., an object code, an assembly language, or ahigh-level language such as Fortran, C, C++, JAVA, or HTML) for use withvarious operating systems or operating environments. The source code maydefine and use various data structures and communication messages. Thesource code may be in a computer executable form (e.g., via aninterpreter), or the source code may be converted (e.g., via atranslator, assembler, or compiler) into a computer executable form.

The computer program may be fixed in any form (e.g., source code form,computer executable form, or an intermediate form) either permanently ortransitorily in a tangible storage medium, such as a semiconductormemory device (e.g., a RAM, ROM, PROM, EEPROM, or Flash-ProgrammableRAM), a magnetic memory device (e.g., a diskette or fixed disk), anoptical memory device (e.g., a CD-ROM), a PC card (e.g., PCMCIA card),or other memory device. The computer program may be fixed in any form ina signal that is transmittable to a computer using any of variouscommunication technologies, including, but in no way limited to, analogtechnologies, digital technologies, optical technologies, wirelesstechnologies (e.g., Bluetooth), networking technologies, andinternetworking technologies. The computer program may be distributed inany form as a removable storage medium with accompanying printed orelectronic documentation (e.g., shrink wrapped software), preloaded witha computer system (e.g., on system ROM or fixed disk), or distributedfrom a server or electronic bulletin board over the communication system(e.g., the Internet or World Wide Web).

Hardware logic (including programmable logic for use with a programmablelogic device) implementing all or part of the functionality previouslydescribed herein may be designed using traditional manual methods, ormay be designed, captured, simulated, or documented electronically usingvarious tools, such as Computer Aided Design (CAD), a hardwaredescription language (e.g., VHDL or AHDL), or a PLD programming language(e.g., PALASM, ABEL, or CUPL).

Programmable logic may be fixed either permanently or transitorily in atangible storage medium, such as a semiconductor memory device (e.g., aRAM, ROM, PROM, EEPROM, or Flash-Programmable RAM), a magnetic memorydevice (e.g., a diskette or fixed disk), an optical memory device (e.g.,a CD-ROM), or other memory device. The programmable logic may be fixedin a signal that is transmittable to a computer using any of variouscommunication technologies, including, but in no way limited to, analogtechnologies, digital technologies, optical technologies, wirelesstechnologies (e.g., Bluetooth), networking technologies, andinternetworking technologies. The programmable logic may be distributedas a removable storage medium with accompanying printed or electronicdocumentation (e.g., shrink wrapped software), preloaded with a computersystem (e.g., on system ROM or fixed disk), or distributed from a serveror electronic bulletin board over the communication system (e.g., theInternet or World Wide Web).

The present invention may be embodied in other specific forms withoutdeparting from the true scope of the invention. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive.

1. A computer-aided modeling system comprising: a knowledge managementsystem for managing a set of modeling rules; and a computer-aided designsystem controlled by the knowledge management system, wherein theknowledge management system generates instructions for modeling ageometric structure based on the set of modeling rules and communicatesthe instructions to the computer-aided design system for generating amodel of the geometric structure.
 2. A computer-aided modeling systemaccording to claim 1, wherein the knowledge management system comprisesa knowledge management application in communication with thecomputer-aided design system through an application program interface ofthe computer-aided design system.
 3. A computer-aided modeling systemaccording to claim 2, wherein the knowledge management system furthercomprises a knowledge storage application in communication with theknowledge management application for storing the set of rules in acentral database and communicating the set of rules to the knowledgemanagement application.
 4. A computer-aided modeling system according toclaim 3, wherein the knowledge management system further comprises aknowledge acquisition application in communication with the knowledgestorage application for generating the set of rules and communicationthe set of rules to the knowledge storage application for storage in thecentral database.
 5. A computer-aided modeling system according to claim1, further comprising a graphical user interface, wherein the knowledgemanagement system produces a graphical display on the graphical userinterface, the graphical display comprising a first portion includinginformation from the knowledge management system and a second portionincluding information from the computer-aided design system.
 6. Acomputer-aided modeling system according to claim 5, wherein the secondportion includes a display window generated by the computer-aided designsystem.
 7. A computer-aided modeling system according to claim 6,wherein the display window includes a graphical representation of thegeometric structure.
 8. A computer-aided modeling system according toclaim 7, wherein the display window further includes controls formanipulating the graphical representation of the geometric structure. 9.A computer-aided modeling system according to claim 1, wherein the setof rules includes at least one rule relating to a non-geometricattribute of the geometric structure.
 10. A computer-aided modelingsystem according to claim 9, wherein the at least one rule relating to anon-geometric attribute includes a rule for determine a cost of thegeometric structure.
 11. A computer-aided modeling system according toclaim 9, wherein the at least one rule relating to a non-geometricattribute includes a rule for defining a process.
 12. A computer-aidedmodeling system according to claim 1, wherein the set of rules includesat least one rule relating to a class having a plurality of geometricstructures.
 13. A computer-aided modeling system according to claim 1,wherein the set of rules includes at least one rule relating to ageometric structure defined in the computer-aided design system.
 14. Acomputer-aided modeling system according to claim 1, wherein thecomputer-aided design system comprises a three-dimensionalcomputer-aided design system.
 15. A computer-aided modeling systemaccording to claim 14, wherein the three-dimensional computer-aideddesign system is SOLIDWORKS™.
 16. A computer-aided modeling systemaccording to claim 14, wherein the computer-aided design system furthercomprises a two-dimensional computer-aided design system.
 17. Acomputer-aided modeling system according to claim 16, wherein thetwo-dimensional computer-aided design system is VISIO™.
 18. A method forcomputer-aided design modeling, the method comprising: generatinginstructions for modeling a geometric structure based on a set ofmodeling rules; and communicating the instructions to a computer-aideddesign system for generating a model of the geometric structure.
 19. Amethod according to claim 18, wherein generating instructions formodeling a geometric structure based on a set of modeling rulescomprises obtaining the set of modeling rules from a central databaseover a communication network.
 20. A method according to claim 18,wherein the computer-aided design system comprises an applicationprogram interface, and wherein communicating the instructions to acomputer-aided design system comprises communicating the instructions tothe computer-aided design system through the application programinterface.
 21. A method according to claim 18, further comprising:producing a graphical display on a graphical user interface, thegraphical display comprising a first portion including informationrelating to the set of modeling rules and a second portion includinginformation from the computer-aided design system.
 22. A methodaccording to claim 21, wherein producing a graphical display on agraphical user interface comprises: directing a window display generatedby the computer-aided design system to be displayed on the graphicaluser interface.
 23. A method according to claim 22, wherein the displaywindow includes a graphical representation of the geometric structure.24. A method according to claim 23, wherein the display window furtherincludes controls for manipulating the graphical representation of thegeometric structure.
 25. A method according to claim 18, wherein the setof rules includes at least one rule relating to a non-geometricattribute of the geometric structure.
 26. A method according to claim25, wherein the at least one rule relating to a non-geometric attributeincludes a rule for determine a cost of the geometric structure.
 27. Amethod according to claim 25, wherein the at least one rule relating toa non-geometric attribute includes a rule for defining a process.
 28. Amethod according to claim 18, wherein the set of rules includes at leastone rule relating to a class having a plurality of geometric structures.29. A method according to claim 18, wherein the set of rules includes atleast one rule relating to a geometric structure defined in thecomputer-aided design system.
 30. A method according to claim 18,wherein the computer-aided design system comprises a three-dimensionalcomputer-aided design system.
 31. A method according to claim 30,wherein the three-dimensional computer-aided design system isSOLIDWORKS™.
 32. A method according to claim 30, wherein thecomputer-aided design system further comprises a two-dimensionalcomputer-aided design system.
 33. A method according to claim 32,wherein the two-dimensional computer-aided design system is VISIO™. 34.Apparatus for computer-aided design modeling, the apparatus comprising:a design modeler for generating instructions for modeling a geometricstructure based on a set of modeling rules; and an interface from thedesign modeler to a computer-aided design system for communicating theinstructions to the computer-aided design system for generating a modelof the geometric structure.
 35. Apparatus according to claim 34, furthercomprising an interface from the design modeler to a central databaseover a communication network for obtaining the set of modeling rulesfrom the central database.
 36. Apparatus according to claim 34, whereinthe computer-aided design system comprises an application programinterface, and wherein the interface from the design modeler to acomputer-aided design system complies with the application programinterface.
 37. Apparatus according to claim 34, further comprising agraphical user interface, wherein the design modeler produces agraphical display on the graphical user interface, the graphical displaycomprising a first portion including information from the design modelerand a second portion including information from the computer-aideddesign system.
 38. Apparatus according to claim 37, wherein the designmodeler directs a window display generated by the computer-aided designsystem to be displayed on the graphical user interface.
 39. Apparatusaccording to claim 38, wherein the display window includes a graphicalrepresentation of the geometric structure.
 40. Apparatus according toclaim 39, wherein the display window further includes controls formanipulating the graphical representation of the geometric structure.41. Apparatus according to claim 34, wherein the set of rules includesat least one rule relating to a non-geometric attribute of the geometricstructure.
 42. Apparatus according to claim 41, wherein the at least onerule relating to a non-geometric attribute includes a rule for determinea cost of the geometric structure.
 43. Apparatus according to claim 41,wherein the at least one rule relating to a non-geometric attributeincludes a rule for defining a process.
 44. Apparatus according to claim34, wherein the set of rules includes at least one rule relating to aclass having a plurality of geometric structures.
 45. Apparatusaccording to claim 34, wherein the set of rules includes at least onerule relating to a geometric structure defined in the computer-aideddesign system.
 46. A method according to claim 34, wherein thecomputer-aided design system comprises a three-dimensionalcomputer-aided design system.
 47. Apparatus according to claim 46,wherein the three-dimensional computer-aided design system isSOLIDWORKS™.
 48. Apparatus according to claim 46, wherein thecomputer-aided design system further comprises a two-dimensionalcomputer-aided design system.
 49. Apparatus according to claim 48,wherein the two-dimensional computer-aided design system is VISIO™. 50.Apparatus comprising a computer readable medium having embodied thereina computer program for computer-aided design modeling, the computerprogram comprising: means for generating instructions for modeling ageometric structure based on a set of modeling rules; and means forcommunicating the instructions to a computer-aided design system forgenerating a model of the geometric structure.
 51. Apparatus accordingto claim 50, wherein the means for generating instructions comprisesmeans for obtaining the set of modeling rules from a central databaseover a communication network.
 52. Apparatus according to claim 50,wherein the computer-aided design system comprises an applicationprogram interface, and wherein the means for communicating theinstructions to the computer-aided design system comprises means forcommunicating the instructions to the computer-aided design systemthrough the application program interface.
 53. Apparatus according toclaim 50, further comprising: means for producing a graphical display ona graphical user interface, the graphical display comprising a firstportion including information relating to the set of modeling rules anda second portion including information from the computer-aided designsystem.
 54. Apparatus according to claim 53, wherein the means forproducing a graphical display on a graphical user interface comprises:means for directing a window display generated by the computer-aideddesign system to be displayed on the graphical user interface. 55.Apparatus according to claim 54, wherein the display window includes agraphical representation of the geometric structure.
 56. Apparatusaccording to claim 55, wherein the display window further includescontrols for manipulating the graphical representation of the geometricstructure.
 57. Apparatus according to claim 50, wherein the set of rulesincludes at least one rule relating to a non-geometric attribute of thegeometric structure.
 58. Apparatus according to claim 57, wherein the atleast one rule relating to a non-geometric attribute includes a rule fordetermine a cost of the geometric structure.
 59. Apparatus according toclaim 57, wherein the at least one rule relating to a non-geometricattribute includes a rule for defining a process.
 60. Apparatusaccording to claim 50, wherein the set of rules includes at least onerule relating to a class having a plurality of geometric structures. 61.Apparatus according to claim 50, wherein the set of rules includes atleast one rule relating to a geometric structure defined in thecomputer-aided design system.
 62. A method according to claim 50,wherein the computer-aided design system comprises a three-dimensionalcomputer-aided design system.
 63. Apparatus according to claim 62,wherein the three-dimensional computer-aided design system isSOLIDWORKS™.
 64. Apparatus according to claim 62, wherein thecomputer-aided design system further comprises a two-dimensionalcomputer-aided design system.
 65. Apparatus according to claim 64,wherein the two-dimensional computer-aided design system is VISIO™. 66.Apparatus for computer-aided design modeling, the apparatus comprising:means for generating instructions for modeling a geometric structurebased on a set of modeling rules; and means for communicating theinstructions to a computer-aided design system for generating a model ofthe geometric structure.